I think it's great you're thinking about getting a yorkie, and you CAN do this if you work 8-5 M-F. We do! Of course, before you get a yorkie, please research the breed A LOT before buying. I'm sure you'll find lots of info on here, and you can always ask questions too! That's what we're here for! Yorkies are a breed that need LOTS of attention, time, and effort-I think a lot of people don't know this, and think they're just getting a cute little dog. Though they're a lot of work, the rewards you get back from them are completely worth it!
Now, about working during the day: The thing to remember is that until your yorkie is old enough and/or pee pad trained, you'll need to get home to let him/her out to potty. They're usually pretty good about not peeing where they sleep, but both of my dogs have surprised me on this one! Sometimes the "puppy" in them is just too much-but it's usually a fluke if they do this.
I would strongly recommend an x-pen for the days while you're gone, rather than a crate. You can put your puppy's pee pad, toys, food, water, and bed in there, and it's like their own little "room". I would recommend putting something waterproof and stain resistant under the pen to save your floors, even if you have hard floors. It's much easier to throw something in the laundry than it is to scrub floors in case of messes. And they will happen! Even with Milli being 8 months old now, we still have messy pen days! I use a piece of material that is rubber on one side and flannel on the other-it's made for making waterproof crib sheets for babies. I put the flannel side down on the floor, and then cover it with an old bed sheet. That way, I can just wash the bed sheet, or if it's really messy, I wash them both.
Also, NEVER bend over the pen wall to pick your young puppy up and out of the pen. Always open the "gate" to the pen. This way, they won't be tempted to jump up or dig underneath it. Once they figure out that UP is the way out, they become jumpers and climbers. If you teach them that UNDER is out, they will try to dig
So, learn from my mistake and let them IN and OUT of the pen-you'll be happy you did in the long run!